Flash lamp



p 1930. J. OSTERMEIER 1,776,637

FLASH LAMP ori inal Filad April 5,1929

Jie ezeian- 7iigmus aermgl cient purity and Patented Sept. 23, 1930 aomuuns os'raammnn, or amnneununm, enmunw rnasn LAMP HEISSUED Application filed April 5, 1929, Serial No. 352,705, and in Germany February 28,- 1929.

The invention relates to flash lamps, more particularly those intended for photographic purposes. which an oxidizable metal inthe form of wire I or ribbon or a flash mixture is lodged in a as-tight transparent bulb which contains a lling of oxygen, of an oxygen-gas mixture, or of a gas that gives ofi oxygen, such as an oxide 0 nitrogen as N O,.at a ressure less than atmospheric. From these nown flash ,lamps the lamp according to the invention differs by the fact that foils of oxidizable substances, more particularly of metals and metal alloys are used as a light producer which foils are so arranged in the bulb as to be in the range of an igniter.

Tests have proved that foils burn away at an extremely hi h speed, when the necessary oxygen or com ination is present in sufliunder suitable pressure.

This rapid combustion takes place if the filling of the bulb contains the same percentage of oxy en as contained in atmospheric am Now, the remarkable difii'erence exists is the combustion, -e. g. of: aluminum foils in the free air takin place very slowly, so to say crawlingly, w ile it takes place with lightnin speed in a bulb filled with pure oxygen -un er a pressure of 150 mm. Hg. As measurements have shown, in this case the average duration of the combustion amounts to 1/40 second. The speed of the combustion can be increased by increasing the pressure 'of the 0 gen. In this case the phenomenon is to be 0 served that the lightning effect of the metal foil when burned in atmospheric air amounts only. to one hundredth of that obtained by burning the foil in an equal quantity of pure oxy en under a pressure of 150 mm. H within t e bulb, the pressure of the gas in t e bulb then being reduced in the proportion of the percentage of oxygen in the atmospheric air, that is in the proportion of about 21 :79. 1

Substances well suited to be used as foils are metals, metal alloys, and are earths, such as aluminum,jcopper, iron, nickel, phosphorbronze,

cerlum, zirconium, and also organic substances. The combustion of the foil may be initiated by any suitable igniting device.

lash lamps are already known in leaky.

In order that the invention can be more easily understood, a preferred embodiment of an electrically ignited flash lamp according to the invention is illustrated by way of example in the drawing, which shows a side View, partly in section of the lamp.

The lamp has the shape of a normal e1 tric incandescent lamp. The bulb 1 possesses the usual glass neck 2 with a sealed-in small tube 3 serving to draw off the air or to fill the bulb with the gas. The conducting wires 4*, 4 are likewise sealed in the neck 2 and extend approximately up to the midst of the bulb. Near their upper ends the wires 4, 4" are held in place by means of a glass piece or rod 5 and are interconnected at their ends by an igniting wire 6. This wire 6 may be fitted with a small fulminating composition 7, to facilitate combustion. The space of the bulb 1 is loosely filled with foils 8 of an oxidizable substance as indicated above. With an egfual wei ht of the foil filling the lighting e ect an the speed of combustion of the filling are the greater, thesmaller the thickness of the foils. The thickness ofthe metal foils amounts to about 0.0005 mm. The pressure of the 120-180 mm. a

' The described lamp need not be equipped with any means for securing it 'agamst explosion when the bulb happens to become This resides in the fact that in case of leakiness of the bulb the combustion of the metal foil takes place very slowly so that a dangerous increase of pressure is avoided due to the heat of combustion being given ofi to the air surroundin the lamp. he only drawback of the lamp ecoming leaky is that the lamp cannot be used as a flash lamp.

As can be seen from the foregoin the igniting wire 6 and the compositlon if any, burn away when electric currentis su plied. The flame of the combustion ignites t e surrounding foil filling 8. Of course, the fillin must be within the range of the igniter. The costs (if production of the lamp are very low as the above-mentioned safet means may be dispensed with and the possib ili1ty is present to use very cheap foil mate ma describe ofivgen in the bulb is between g A further advantage of the described lamp resides in the fact that currents of a Very low voltage can be used to ignite the foil filling, asfoils are extremely easily inflammable 5 due to their small thickness. The voltage of a normal pocket lamp battery is suflicient to cause ignition. This therefore affords the advantage of the use of the lamp without de pending upon an electric supply system.

When used for photographic purposes, the bulb may be fitted inside or outside with a layer of a material, such as a yellow filter or tartrazin that absorbs a portion of the rays of the spectrum of the bulb itself may be made of a material, such as yellow glass, having such an absorbing efi'ect.

What I claim and desire to secure by Letters Patent is 1. A flash lamp particularly for photographic purposes, comprising a closed gastight transparent bulb containing an oxygen gas; and a foil in the bulb adapted to emit light upon combustion thereof with the oxygen and disposed within effective range of an ignition device.

2. A flash lamp particularly for photographic purposes, comprising a closed gastight transparent bulb containing an oxygen gas mixture; a foil in the bulb adapted to emit light upon combustion thereof with the oxygen and disposed Within eflective range of an ignition device; and a screen associated with the bulb for absorbing a portion of the rays of the spectrum.

3. A flash lamp particularly for photographic purposes, comprising a closed gastight transparent bulb containing a gas capable ofyielding oxygen and a foil in the bulb adapted to emit light upon combustion thereof with the oxygen and disposed within effective range of an ignition device, said bulb being adapted to absorb a portion of the rays of the spectrum.

a. A flash lamp particularly for photographic nurposes, comprising a closed gastight bulb having a gas therein; an igniting device in said bulb; and afoil in the bulb adapted to emit light upon combustion thereof with the gas and disposed within effective range of the ignition device.

5. A flash lamp, comprising a bulb filled with a gaseous oxygenic substance at a pressure less than atmospheric an igniting device in said bulb; foil of oxidizable substance in said bulb in the ignition range of said device; and a layer on said bulb of a substance adapted to absorb a portion of the rays of the spectrum. I

6. A flash lamp, comprising a bulb filled with a gaseous oxygenic substance; an igniting device in said bulb; foil of oxidizable substance in said bulb in the ignition range of said device, said bulb being of a material light-emitted, or the J OHAN N ES OSTERMEIER; 

